Worked examples are the principle of demonstrating the work for the learner. This simple but very effective principle allows the facilitator to visually show the learner how to accomplish the desired task. By having an expert show how to accomplish the task, the learner is able to understand and repeat the task quicker and remember the task better.
Reference:
Atkinson, R. K., Derry, S. J., Renkl, A & Wotham, D. (2000). Learning from examples: Instructional principles from the worked examples research. CiteSeer. Retrieved from: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.115.1348